Garden Talk: August 25, 2011

From NGA Editors

Native Bee Basics

Native bees are important and often under-appreciated pollinators. If you'd like to find out more about these helpful insects and what you can do to conserve and protect them on your property and in your community, start by reading about them in Bee Basics: An Introduction to Our Native Bees by Dr. Beatriz Moisset and Dr. Stephen Buchmann.

This forty-four page booklet, published by the USDA Forest Service and Pollinator Partnership, is available as a free download or can be ordered in a print version. With information on bee anatomy, nesting, and foraging needs, along with profiles of native bees and an extensive section on conservation and what you can do to help keep native bee populations healthy, the booklet provides a wealth of information written in an accessible manner. For those who want to delve deeper, there is a helpful resource section.

The Pollinator Partnership website also offers extensive information on all kinds of pollinators.

Lingering Effects of Invasive Species

The ecological disruption caused by invasive plants species is a worldwide problem. The cost of the environmental and economic impact of these invaders is estimated to be in the neighborhood of $1.4 trillion annually! Much research is being done to come up with strategies to control the spread of undesirable plants and minimize their impact on natural ecosystems. Now new research suggests that simply removing invasive species may not return plant communities to their pre-invasion condition.

Part of developing control strategies for invasive plants involves understanding the characteristics that allow certain species to become invasive in the first place, factors such as freedom from natural enemies, disturbance in the environment, and the ability of plants to release substances that prevent competing plants from growing.

To study how the interactions between all of these factors affect the success of an invasive species, investigators from the University of California and the University of Wisconsin studied invasive velvetgrass, Holcus lanatus,(illustrated) and its effect on a native daisy, Erigeron glaucus, in California. As described in an article in Science Daily on August 10, 2011, they found that direct competition between velvetgrass and the daisy accounted for much of its initial success due to the dense growth of the grass and its abundant propagules.

But they also found that velvetgrass altered the structure of the native community of soil organisms, specifically the mycorrhizal fungi in the soil. This change reduced the benefits of the mycorrhizae to the native daisy without having any negative impact on the velvetgrass. And the changes in the soil community persisted even after the velvetgrass was removed, potentially affecting the reestablishment of the native plants.

These findings suggest that studying the negative effects invasive species have on the ecology of the soil has important implications for researchers who are looking at ways to mitigate their effects.

To read more about the effects of invasive plants even after removal, go to: Science Daily.

Move Gypsy Moth Free

The gypsy moth is an introduced insect that is one of the most destructive pests of trees and shrubs ever to reach our shores. Its immature stage, a dark, hairy caterpillar with rows of red and blue spots on its back, is a general feeder that devours more than 450 species of plants! The caterpillars feast on leaves, leaving defoliated plants weakened and perhaps even killed. This pest overwinters as inch-and-a-half long egg masses that look like a clumps of tan or buff-colored hairs on tree trunks, outdoor furniture, or the sides of buildings.

Native to Europe and Asia, the gypsy moth was accidentally introduced in the Boston area in the 1860's and has since spread to much of the eastern United States. There have also been some infestations on the West Coast that came from Asia. In an effort to keep this pest from spreading further, the USDA requires homeowners to inspect and remove gypsy moth egg masses from household goods prior to moving from an infested to a non-infested area.

If you have a move planned, first find out if you are in a gypsy moth-quarantined area by checking out the Your Move Gypsy Moth Free website. There you can also learn how to inspect your outdoor household articles such as lawn furniture, yard equipment, outdoor toys, and the like, for gypsy moth egg masses and remove them. Without checking, you can unwittingly bring the moth with you and risk harm to the landscape trees and shrubs and natural forests in your new community.

Print out a handy self-inspection checklist or download a brochure with all the information you need to move safely and comply with federal law. To hone your detection skills, you can even play the fun, on-line Bust-a-Moth game.

Landscape Problem Solver

We all probably wish we had an experienced gardener we could call on for advice whenever problems arise in the garden. For those of us without such a fount of knowledge, the Landscape Problem Solver from the University of Maryland's Home Garden Information Center may be the next best thing.

This site offers photographic keys to help diagnose and solve plant problems, using integrated pest management principles. Choose from a list of broad categories, such as shade trees, vegetables, or houseplants. Then select the affected plant part from the drop-down menu. This brings up a photographic selection of symptoms. Choose the one that seems to fit and you get a page of information on the problem, its cause, and environmentally responsible ways to treat it. There is also information on how to look at a plant to best assess its symptoms, beneficial insects, and emerging pest threats.

The information has been put together with the Mid-Atlantic region as its focus, but there is lots of good information that will be of use to gardeners in other parts of the country.